Heat engine and a method of putting this engine into action

ABSTRACT

In an otherwise conventionally designed piston and cylinder internal combustion engine, is provided an additional, fixed volume, combustion chamber, which can communicate with the variable volume enclosure provided by the piston and cylinder. The engine operates on a six-stroke cycle. During the first stroke, air is drawn into the enclosure; during the second, the air is compressed and introduced into the chamber; during the third, the chamber is sealed off, more air is drawn into the enclosure, fuel is injected into the chamber and the resultant mixture in the chamber is ignited; during the fourth, the air in the enclosure is compressed while combustion still carries on in the chamber; during the fifth, the chamber is made to communicate with the enclosure to bring the burning mixture into contact with the compressed air thereby to complete combustion and to drive the piston; and during the sixth, the burnt gases are exhausted. The working stroke is thus the fifth.

United States Patent Milisavljevic 51 May 16, 1972 Milorad Milisavljevic, Promenade des Anglois 181, F-06-Nice, France 22 Filed: Dec. 14,1970

21 Appl.No 97,515

[72] Inventor:

Primary Examiner-Wendell E. Burns Att0meyKa.rl F. Ross [57] ABSTRACT In an otherwise conventionally designed piston and cylinder internal combustion engine, is provided an additional, fixed volume, combustion chamber, which can communicate with the variable volume enclosure provided by the piston and cylinder. The engine operates on a six-stroke cycle. During the first stroke, air is drawn into the enclosure; during the second, the air is compressed and introduced into the chamber; during the third, the chamber is sealed off, more air is drawn into the enclosure, fuel is injected into the chamber and the resultant mixture in the chamber is ignited; during the fourth, the air in the enclosure is compressed while combustion still carries on in the chamber; during the fifth, the chamber is made to communicate with the enclosure to bring the burning mixture into contact with the compressed air thereby to complete combustion and to drive the piston; and during the sixth, the burnt gases are exhausted. The working stroke is thus the fifth.

2 Claims, 3 Drawing Figures HEAT ENGINE AND A METHOD OF PUTTING THIS ENGINE INTO ACTION This invention relates to heat engines.

Achieving good combustion of a gaseous mixture in the cylinders of explosion or internal combustion engines has at all times given rise to particularly thorough research work both as regards the characteristics of the kinds of fuel used and the manner of preparing the gaseous mixture, and as regards the structure of the engines as such, in particular of their explosion chamber. It is known that the thermal efi'rciency level and, hence, the extent to which such an engine becomes sooted up and the degree of relative purity of the gases that are exhausted at the end of each operative cycle are dependent on the quality of the combustion that is achieved.

Despite all the efforts that have been made, it has not yet been possible to design low cost piston heat engines, i.e. engines intended for instance to be fitted in mass produced cars, with which it is possible to achieve complete combustion of the fuel being used. The constructions that have been designed within this particular context generally involve relatively complex mechanical principles such as the use of feed compressors, of spherical or like explosions chambers and of a multiple-carburettor or injection feed system.

Such complexity not only leads to an increase in the cost price of the engines but also of their maintenance costs.

Moreover, an elaborate engine is obviously more subject to breakdowns of a mechanical nature than an engine of conventional design.

An object of the invention is to enable the production of a heat engine of particularly high thermal efficiency and of simple design, corresponding largely to that of an explosion or internal combustion engine of conventional design.

According to the present invention there is provided a heat engine comprising a combustion chamber, a device for admitting fuel into this chamber, a member for igniting the fuel, means for controlling said device and said member, a cylinder, a piston slidably mounted in the cylinder and defining therewith an enclosure of variable volume, a rod and crank assembly connecting the piston to a rotary shaft, a valve for admitting fresh air into the enclosure, a valve for exhausting the combustion gas, means for controlling each valve, a passage connecting the combustion chamber and the enclosure, a member for closing this passage and means for alternately bringing this closure member into the closed and open positions, wherein the means for controlling the device for admitting fuel into the chamber and for controlling the ignition member, the means for controlling the valves and the means for controlling the closure member are kinematically dependent on said rotary shaft and comprise their own programme for the actuation of the elements to be controlled, wherein the actuation programme for the closure member is adapted to place the closure member in the closed or open position at the beginning of a first stroke of the piston from its top dead point (T.D.P.) to its bottom dead point (B.D.P.), to place the closure member in the open position at the beginning of a second stroke of the piston, corresponding to the return of the piston to its T.D.P., to place the closure member in the closed position from the beginning of a third stroke until the end of a fourth stroke of the piston, corresponding, respectively, to the subsequent displacements of the piston from its T.D.P. to its B.D.P. and vice versa, and to place the closure member in the open position from the beginning of a fifth stroke and until the end of a sixth stroke of the piston, corresponding, respectively, to two further subsequent displacements of the piston from its T.D.P. to its B.D.P. and vice versa, wherein the actuation programme for the intake valve is adapted to open this valve at the beginning of said first piston stroke, to close this valve at the beginning of said second stroke, to open this valve at the beginning of said this stroke, and to close this valve from the beginning of said fourth stroke, wherein the actuation programme for the exhaust valve is adapted to open this valve at least during said sixth stroke, and wherein the actuation programme for the device for admitting fuel into the chamber and the actuation programme for the ignition member are adapted to control, from the beginning of said third stroke, first the intake of fuel and then the ignition of this fuel, the whole arrangement being such as to achieve, in the chamber, constant volume combustion during said third and fourth strokes and, in the closure, a variable volume combustion during said fifth stroke.

The invention also provides a method of putting this heat engine into action, which comprises, during said first stroke, causing an intake of fresh air into the enclosure, during said second stroke, compressing this air and introducing it into the chamber, during said third stroke, sealing off the chamber from the enclosure and causing firstly a new intake of fresh air into the enclosure and secondly the admission of a charge of fuel into the chamber and the ignition of the resultant mixture of air and fuel, during said fourth stroke, compressing within the closure the fresh air that was admitted during the third stroke and letting the combustion that has started in the chamber to carry on, during said fifth stroke, putting the chamber and the enclosure into communication to bring into contact the mixture that is in the process of combustion in said chamber and the compressed airin the enclosure thereby to complete this combustion and to drive the piston through expansion of the burnt gases produced in the enclosure, and, during said sixth stroke, exhausting at least the burnt gases filling the enclosure.

The accompanying drawings illustrate, by way of example and very schematically, one embodiment of the heat engine provided by the present invention.

In the drawings:

FIG. 1 is a vertical section through this engine;

FIG. 2 is a plan view ofFlG. l; and

FIG. 3 is an explanatory diagram.

The heat engine illustrated in FIG. 1 and 2 comprises a cylinder 1 to the lower part of which is secured a crank-case 2, containing a lubricant L, and the upper part of which carries a head 3.

In the cylinder 1 is mounted a sliding piston 4 which is kinematically connected to a shaft 5, extending in a direction perpendicular to the plane of FIG. 1, by a rod 6 and crank 7 assembly. The shaft 5 carries a flywheel, not shown, for momentarily storing kinematic energy intended to be restored to the shaft during the idle strokes of the engine, i.e. the strokes during which the piston is not having a working or driving action.

The side wall of the cylinder 1 is formed in its upper portion with two diametrically opposite ports f and f The port f forms an opening for the admission into the cylinder of fresh air fed to the heat engine from a suitable air inlet and through a duct, both not shown, terminating at a conduit 8 solid with the cylinder 1. This port f can be closed by a valve 9 which is subjected, firstly, to the action of a return spring 10 tending to keep it in the open position and, secondly, to the action of a cam 11 solid with a shaft 12 and intended to provide a programmed control of the valve 9 as described further on. The shaft 12 is driven off the shaft 5, at a speed equal to one third of that of this shaft, by a transmission not shown.

The port f establishes communication between the cylinder 1 and an intermediate chamber 13 which is disposed in an offcenter position and which communicates with a chamber 14, formed in the thickness of the head 3, via a port f which port can be closed through the intermediary of a valve 15, subjected to the action of a spring 16 opposing the closing action of this valve, and of a cam 17 solid with a shaft 18. This cam 17 is intended to control the programmed closing and opening action of the valve 15 in the manner described further on. The shaft 18 is also driven off the shaft 5, at a speed equal to one third of that of this shaft, by a transmission not shown.

As will be observed from FIG. 1, the top wall of the chamber 14 is formed with a port 12, providing an outlet opening. This port can be closed by a valve 19 which a spring 20 tends to keep in the open position and which is subjected to the action of a cam 21 keyed on a shaft 22. This shaft, like the shafts 12 and 18, is rotated off the shaft 5 via a transmission, not shown, providing a 1:3 gear reduction ratio.

On the head 3 are also mounted a fuel injector 23, which is supplied under pressure by a pump not shown, and a sparking plug 24 which is connected to a voltage pulse source, also not shown. The injector and the sparking plug are both engaged at one end, not visible in the drawing, inside the chamber 14.

Cams not shown, which are kinematically dependent on the shaft 5, cause at the appropriate moment fuel to be injected into the chamber 14 and to be ignited by the plug.

The described heat engine has a six-stroke cycle and FIG. 3 shows the actuation programme for the three valves 9, and 19, for the injector 23 and for the plug 24 in dependence on these six strokes (I, II, III, IV, V and VI).

This programme corresponds to the aspect of the profile of the cams for actuating these elements, the rises and the dips" of each cam outline succeeding each other, in fact, in the order order and over an angular length of each can corresponding to those of the outline of the FIG. 3 diagram.

It should be pointed out that these cams are angularly keyed on their respective shafts so as to occupy positions corresponding to the beginning or to the end of a cycle when the position 4 is at the top dead point and is about to move towards its bottom dead point, under the shaft 5.

At the beginning of the first stroke, the valves 15 and 9, which were previously in the open position and in the closed position respectively, are moved to their closed position and their open position respectively, whereas the valve 19 is kept in its closed position. Consequently, the chamber 14 is cut off from both the cylinder 1 and the ambient atmosphere, and the piston 4, through moving from the top dead point to the bottom dead point, sets up in the cylinder 4 a partial vacuum causing air to be drawn in through the port f,.

At the end of the first stroke, the cams l7, l1 and 21 respectively cause the valve 15 to open, the valve 9 to close and the valve 19 to open. Since the piston 4 is returning to its top dead point and the cylinder is in communication with the chamber 14, the air that is drawn into the cylinder during the first stroke is forced into this chamber, partly escapes through the port f, and scavenges the cylinder and the chamber 14. This scavenging action quickly ceases however since the cam 21 causes the valve 19 to close (FIG. 3) when the piston 4 has just started to move towards its top dead point.

Once the valve 19 has been closed, the piston 4 continues to force back the air filling the cylinder by compressing it in the chamber 4. This compression ends when the piston has reached its top dead point (end of the second stroke).

At that time, the earns 17 and 11 respectively cause the valve 15 to close and the valve 9 to open so that the chamber 14 is again out off from the cylinder 11 and so that the port f enabling air to enter the cylinder 1, is opened.

The piston 4 then moves from its top dead point to its bottom dead point (third stroke), thus setting up a partial vacuum in the cylinder which again causes air to be drawn into the latter. Moreover, from the beginning of this movement, the cam actuating the injector 23 causes a charge of fuel to be injected into the chamber 14 (line 23 in FIG. 3) to form in this chamber a gaseous mixture which is immediately ignited by the plug 24 under the control of its associated cam.

Since the chamber 14 is completely closed, the combustion that takes place therein does so under constant volume conditions. This combustion continues moreover during a fourth stroke in the course of which both the valve 15 and the valve 19 are kept in their closed position (FIG. 3lines 15 and 19).

In view of the fact that, in the chamber 14, combustion can carry on for a relatively long period of time, corresponding to that taken by two strokes of the described cycle, this combustion can take place in a particularly complete manner and the pressure energy obtained from this combustion will be very considerable.

Thus, because of this extended combustion, it will even be possible to use poor quality fuel or fuel usually having a low flame-propagation rate.

Since the cam 11 closes the valve 9 at the end of the third stroke and the cylinder 1 is then filled with air, the piston 4, which is still driven by the flywheel not shown, will compress this air during the fourth stroke of the piston.

At the end of this fourth stroke, the cam 17 causes the valve 15 to open and the chamber 14 and the cylinder 1 can then communicate, whereas the valves 19 and 9 are kept in the closed position by their respective cams. Consequently, the combustion, which previously took place under constant volume conditions, can now be completed under variable volume conditions in the cylinder 1 by virtue of the new intake of air (fifth stroke): the piston 4 is thus subjected to a particularly violent driving force due to the expansion of both the gases contained in the chamber 14 and those contained in the cylinder. It is thus this fifth stroke which is the working or driving stroke in the described heat engine.

At the end of this stroke, the valve 19 is moved to the open position whereas the valves 15 and 9 are kept in the open position and in the closed position respectively.

It follows therefore than when the piston rises from its bottom dead point to its top dead point (sixth stroke), the burnt gases contained in the cylinder 1 are forced into the chamber 14, discharging in so doing those in the chamber itself through the port )2, whereupon they are expelled from this chamber but only partially so since, upon the piston 4 reaching its top dead point, there will subsist in the chamber 14 a charge of burnt gases from the cylinder 1, corresponding to the volume of this chamber. The end of the sixth stroke coincides with the end of a cycle, the following cycle taking place as described above.

It should be pointed out that the charge of burnt gases remaining in the chamber 14, at the end of each cycle, is exhausted from this chamber at the beginning of the second stroke of the subsequent cycle by the scavenging action taking place during compression of the air drawn into the cylinder during the first stroke, this scavenging action bring achieved, as described earlier, by momentarily opening the valve 19 (see line 19, FIG. 3).

Although in the FIG. 3 diagram it was envisaged keeping the valve 15 in the closed position during the first stroke of each cycle, it would be possible, by way of variant, to leave this valve open during this first stroke and not to open momentarily the valve 10 at the beginning of the second stroke. In this way, the sucking action caused in the cylinder by the movement of the piston from its top dead point towards its bottom dead point would cause fresh air and the burnt gases contained in the chamber to be drawn into the cylinder. This air and these gases would form a combustion-promoting mixture filling the whole of the heat engine and having even quite a high temperature, the value of which, which is slightly increased by the compression obtained during the second stroke of the cycle, could in some cases reach a threshold that greatly facilitates combustion in the chamber 14 (during the third and fourth strokes). This preheating action of the combustion gaseous mixture will prove to be of great interest for operating the described heat engine in particularly cold climates or at higher altitudes.

Such a heat engine can operate satisfactorily at even quite high altitudes, the cycle which is particular thereto including two air intake and compression strokes instead of only one, as is the case with a four-stroke engine.

Although in the preceding description, reference is made to a heat engine with only one constant volume combustion chamber 14 working in cooperation with a single cylinder and piston unit, the energy required to drive the piston during the cycle strokes other than the fifth being supplied by a flywheel, it is clear that it is possible to conceive, as in the case of fourstroke engines, an engine comprising several cylinder and combustion chamber units. Preferably such an engine will comprise a number of cylinder and combustion chamber units equal to six or to a multiple of six, it being understood that the strokes of the pistons would then be so programmed that the working or driving strokes would follow each other from unit to unit whereby the engine shaft may be driven without resorting to a flywheel.

I claim:

1. A heat engine comprising a combustion chamber, a device for admitting fuel into this chamber, a member for igniting the fuel, means for controlling said device and said member, a cylinder, a piston slidably mounted in the cylinder and defining therewith an enclosure of variable volume, a rod and crank assembly connecting the piston to a rotary shaft, a valve for admitting fresh air into the enclosure, a valve for exhausting the combustion gas, means for controlling each valve, a passage connecting the combustion chamber and the enclosure, a member for closing this passage and means for alternately bringing this enclosure member into the closed and open positions, wherein the means for controlling the device for admitting fuel into the chamber and for controlling the ignition member, the means for controlling the valves and the means for controlling the closure member are kinematically dependent on said rotary shaft and comprise their own programme for the actuation of the elements to be controlled, wherein the actuation programme for the closure member is adapted to place the closure member in the closed or open position at the beginning of a first stroke of the piston from its top dead point (T.D.P.) to its bottom dead point (B.D.P.), to

place the closure member in the open position at the beginning of a second stroke of the piston, corresponding to the return of the piston to its T.D.P,, to place the closure member in the closed position from the beginning of a third stroke until the end of a fourth stroke of the piston, corresponding, respectively, to the subsequent displacements of the piston from its T.D.P. to its B.D.P. and vice versa, and to place the closure member in the open position from the beginning of a fifth stroke and until the end of a sixth stroke of the piston, corresponding, respectively, to two further subsequent displacements of the piston from its T.D.P. to its B.D.P. and vice versa, wherein the actuation programme for the intake valve is adapted to open this valve at the beginning of said first stroke of the engine, to close this valve at the beginning of said second stroke, to open this valve at the beginning of said third stroke, and to close this valve from the beginning of said fourth stroke, wherein the actuation programme for the exhaust valve is adapted to open this valve at least during said sixth stroke, and wherein the actuation programme for the device for admitting fuel into the chamber and the actuation programme for the ignition member are adapted to control, from the beginning of said third stroke, first the intake of fuel and then the ignition of this fuel, the whole arrangement being such as to achieve, in the chamber, constant volume combustion during said third and fourth strokes and, in the enclosure, a variable volume combustion during said fifth stroke.

2. A method of putting the heat engine according to claim 1 into action, which comprises, during said first stroke, causing an intake of fresh air into the enclosure, during said second stroke, compressing this air and introducing it into the chamber, during said third stroke, sealing off the chamber from the enclosure and causing firstly a new intake of fresh air into the enclosure and secondly the admission of a charge of fuel into the chamber and the ignition of the resultant mixture of air and fuel, during said fourth stroke, compressing within the enclosure the fresh air that was admitted during the third stroke and letting the combustion that has started in the chamber to carry on, during said fifth stroke, putting the chamber and the enclosure into communication to bring into contact the mixture that is in the process of combustion in said chamber and the compressed air in the enclosure thereby to complete this combustion and to drive the piston through expansion of the burnt gases produced in the enclosure, and, during said sixth stroke, exhausting at least the burnt gases filling the enclosure. 

1. A heat engine comprising a combustion chamber, a device for admitting fuel into this chamber, a member for igniting the fuel, means for controlling said device and said member, a cylinder, a piston slidably mounted in the cylinder and defining therewith an enclosure of variable volume, a rod and crank assembly connecting the piston to a rotary shaft, a valve for admitting fresh air into the enclosure, a valve for exhausting the combustion gas, means for controlling each valve, a passage connecting the combustion chamber and the enclosure, a member for closing this passage and means for alternately bringing this enclosure member into the closed and open positions, wherein the means for controlling the device for admitting fuel into the chamber and for controlling the ignition member, the means for controlling the valves and the means for controlling the closure member are kinematically dependent on said rotary shaft and comprise their own programme for the actuation of the elements to be controlled, wherein the actuation programme for the closure member is adapted to place the closure member in the closed or open position at the beginning of a first stroke of the piston from its top dead point (T.D.P.) to its bottom dead point (B.D.P.), to place the closure member in the open position at the beginning of a second stroke of the piston, corresponding to the return of the pisTon to its T.D.P., to place the closure member in the closed position from the beginning of a third stroke until the end of a fourth stroke of the piston, corresponding, respectively, to the subsequent displacements of the piston from its T.D.P. to its B.D.P. and vice versa, and to place the closure member in the open position from the beginning of a fifth stroke and until the end of a sixth stroke of the piston, corresponding, respectively, to two further subsequent displacements of the piston from its T.D.P. to its B.D.P. and vice versa, wherein the actuation programme for the intake valve is adapted to open this valve at the beginning of said first stroke of the engine, to close this valve at the beginning of said second stroke, to open this valve at the beginning of said third stroke, and to close this valve from the beginning of said fourth stroke, wherein the actuation programme for the exhaust valve is adapted to open this valve at least during said sixth stroke, and wherein the actuation programme for the device for admitting fuel into the chamber and the actuation programme for the ignition member are adapted to control, from the beginning of said third stroke, first the intake of fuel and then the ignition of this fuel, the whole arrangement being such as to achieve, in the chamber, constant volume combustion during said third and fourth strokes and, in the enclosure, a variable volume combustion during said fifth stroke.
 2. A method of putting the heat engine according to claim 1 into action, which comprises, during said first stroke, causing an intake of fresh air into the enclosure, during said second stroke, compressing this air and introducing it into the chamber, during said third stroke, sealing off the chamber from the enclosure and causing firstly a new intake of fresh air into the enclosure and secondly the admission of a charge of fuel into the chamber and the ignition of the resultant mixture of air and fuel, during said fourth stroke, compressing within the enclosure the fresh air that was admitted during the third stroke and letting the combustion that has started in the chamber to carry on, during said fifth stroke, putting the chamber and the enclosure into communication to bring into contact the mixture that is in the process of combustion in said chamber and the compressed air in the enclosure thereby to complete this combustion and to drive the piston through expansion of the burnt gases produced in the enclosure, and, during said sixth stroke, exhausting at least the burnt gases filling the enclosure. 